PPU (NES)
More info
- Creator
- Ricoh, Nintendo
- Released
- 1983
- Type
- Graphics chip
The NES graphics chip, Ricoh's 2C02 — a machine that draws tiles and sprites line by line and refuses to be interrupted while it does.
The PPU (Picture Processing Unit) builds a 256×240 image from pattern tables, nametables and 256 bytes of OAM describing 64 sprites. On NTSC it runs at three times the CPU clock, and its only window to the processor is eight registers mapped at $2000–$2007.
Its limits shaped the console's whole look. A maximum of eight sprites per scanline produced sprite flicker. Video memory can only be written safely during VBlank, so game logic had to queue graphics changes until then. Mid-frame tricks such as status bars leaned on the sprite zero hit. The PAL variant is the 2C07.